Woolly Mammoth - Frozen Specimens

Frozen Specimens

Woolly mammoth fossils have been found in many different types of deposits, including former rivers and lakes, and also in "Doggerland" in the North Sea, which was dry at times during the ice age. Such fossils are usually fragmentary and contain no soft tissue. Apart from frozen remains, the only soft tissue known is from a specimen that was preserved in a petroleum seep in Starunia, Poland. Frozen remains of woolly mammoths have been found in the northern parts of Siberia and Alaska, with far fewer finds in the latter. Such remains are mostly found above the Arctic Circle, in permafrost. It appears that soft tissue was less likely to be preserved between 30,000 and 15,000 years ago, perhaps because the climate was milder during that period. Most specimens have partially degraded prior to discovery, due to exposure or to being scavenged. This "natural mummification" required the animal to have been buried rapidly in liquid or semi-solids such as silt, mud and icy water, which then froze. The presence of undigested food in the stomach and seed pods still in the mouth of many of the specimens suggests neither starvation nor exposure are likely. The maturity of this ingested vegetation places the time of death in autumn rather than in spring, when flowers would be expected. The animals may have fallen through ice into small ponds or potholes, entombing them. Many are certainly known to have been killed in rivers, perhaps through being swept away by floods. In one location, by the Berelekh River in Yakutia in Siberia, more than 8,000 bones from at least 140 mammoths have been found in a single spot, apparently having been swept there by the current.

Between 1692 and 1806, only four descriptions of frozen mammoths were published in Europe. None of the remains of those five were preserved, and no complete skeleton was recovered during that time. While frozen woolly mammoth carcasses had been excavated by Europeans as early as 1728, the first fully documented specimen was discovered near the delta of the Lena River in 1799 by Ossip Schumachov, a Siberian hunter. Schumachov let it thaw until he could retrieve the tusks for sale to the ivory trade. While in Yakutsk in 1806, Michael Friedrich Adams heard about the frozen mammoth. Upon arrival at the location, Adams discovered that wild animals had eaten most of the organs and flesh of the mammoth, including the trunk. He examined the carcass and realised what was left would still be the most complete mammoth recovered by that time. Adams recovered the entire skeleton, apart from the tusks, which Shumachov had already sold, and one foreleg, most of the skin, and nearly 18 kg (40 lb) of hair. During his return voyage he purchased a pair of tusks that he believed were the ones that Shumachov had sold. Adams brought it to the Zoological Museum of the Zoological Institute of the Russian Academy of Sciences, and the task of mounting the skeleton was given to Wilhelm Gottlieb Tilesius. The Kunstkamera, the museum established by Peter the Great, contained the skeleton of an Indian elephant that could be used as reference. This was one of the first attempts at reconstructing the skeleton of an extinct animal. Most of the reconstruction is correct, but Tilesius placed each tusk in the opposite socket, so that they curved outward instead of inward. The error was not corrected until 1899, and the correct placement of mammoth tusks was still a matter of debate into the twentieth century.

The 1901 excavation of the "Berezovka mammoth" is the best documented of the early finds. It was discovered by the Berezovka River, and the Russian authorities financed its excavation. Its head was exposed, and the flesh had been scavenged. The animal still had grass between its teeth and on the tongue, showing that it had died suddenly. The entire expedition took 10 months, and the specimen had to be cut to pieces before it could be transported to St. Petersburg. It was identified as a 35–40 year old male, which had died 35,000 years ago. One of its shoulder blades was broken, which may have happened when it fell into a crevasse.

By 1929, the remains of 34 mammoths with frozen soft tissues (skin, flesh, or organs) had been documented. Only four of them were relatively complete. Since then, about that many more have been found. In most cases, the flesh showed signs of decay before its freezing and later desiccation. Since 1860, Russian authorities have offered rewards of up to руб.1000 for finds of frozen woolly mammoth carcasses. Often such finds were kept secret due to superstition. Several carcasses have been lost because they were not reported, and one was fed to dogs. In more recent years, scientific expeditions have been devoted to finding carcasses instead of relying solely on chance encounters.

In 1977, the well-preserved carcass of a seven- to eight-month-old woolly mammoth calf named "Dima" was discovered. This carcass was recovered near a tributary of the Kolyma River in northeastern Siberia. This specimen weighed approximately 100 kg (220 lb) at death and was 104 cm (41 in) high and 115 cm (45 in) long. Radiocarbon dating determined that "Dima" died about 40,000 years ago. Its internal organs are similar to those of modern elephants, but its ears are only one-tenth the size of those of an African elephant of similar age. A less complete juvenile, nicknamed "Mascha", was found on the Yamal Peninsula in 1988. It was 3–4 months old, and a laceration on its right foot may have been the cause of death. It is the westernmost frozen mammoth found.

In 1997, a piece of mammoth tusk was discovered protruding from the tundra of the Taymyr Peninsula in Siberia, Russia. In 1999, this 20,380 year old carcass and 25 tons of surrounding sediment were transported by an Mi-26 heavy lift helicopter to an ice cave in Khatanga. In October 2000, the careful defrosting operations in this cave began with the use of hairdryers to keep the hair and other soft tissues intact.

In 2007, the carcass of a female calf nicknamed "Lyuba" was discovered near the Yuribei River, where it had been buried for 41,800 years. By cutting a section through a molar and analysing its growth lines, they found that the animal had died at the age of one month. The mummified calf weighed 50 kg (110 lb), was 85 cm (33 in) high and 130 cm (51 in) in length. At the time of discovery, its eyes and trunk were intact and some fur remained on its body. Its organs and skin are very well preserved. "Lyuba" is believed to have been suffocated by mud in a river that its herd was crossing. After death, its body may have been colonised by bacteria that produce lactic acid, which "pickled" it, preserving the mammoth in a nearly pristine state.

In 2012, a juvenile was found in Siberia, which had man-made cut marks. Scientists estimated its age at death to be 2.5 years, and nicknamed it "Yuka". Another mammoth discovery was reported in October 2012, when it was excavated on the Taymyr Peninsula. It was dated to 30,000 years old. It was named "Zhenya" after the boy who found it.